The objectives of this Core are to design four identical elastographic systems (common platform), and develop and test their specific hardware/software. Two of the new systems will be used to conduct a clinical study directed by Dr. Brian Garra. The two remaining systems will be used to continue the investigation and development of new algorithms for elastography. This common platform is essential for the program project. Another Core will provide full maintenance of the elastographic systems (software and hardware modifications as needed by the members of the program project). This Core will also develop elastographic phantoms with consistent quality for the projects and their sub-contractors.